function shotg=gaincc(shot,x,z,xshot,zshot)
% GAINCC ... gain a migrated shot record after CC imaging condition
%
% The method of gain correction is simply to compute the radial distance,
% r, from the shot to each image point and to multiply the migrated shot by
% r. For a constant velocity medium, this is the correct gain correction in
% 2D while for 3D it should be r^2. For variable velocity this is a kludge
% but seems to work reasonably well. The best way to gaincorrect a migrated
% shot is to use the deconvolution imaging condition.
%
% shot...input shot
% x ... x coordinates of each column of shot
% z ... z coordinates of each row of shot
% xshot ... xcoordinate of shot
% zshot ... z coordinate of shot
%
% G.F. Margrave, CREWES, 2010
%
% NOTE: This SOFTWARE may be used by any individual or corporation for any purpose
% with the exception of re-selling or re-distributing the SOFTWARE.
% By using this software, you are agreeing to the terms detailed in this software's
% Matlab source file.

% BEGIN TERMS OF USE LICENSE
%
% This SOFTWARE is maintained by the CREWES Project at the Department
% of Geology and Geophysics of the University of Calgary, Calgary,
% Alberta, Canada.  The copyright and ownership is jointly held by
% its 'AUTHOR' (identified above) and the CREWES Project.  The CREWES
% project may be contacted via email at:  crewesinfo@crewes.org
%
% The term 'SOFTWARE' refers to the Matlab source code, translations to
% any other computer language, or object code
%
% Terms of use of this SOFTWARE
%
% 1) This SOFTWARE may be used by any individual or corporation for any purpose
%    with the exception of re-selling or re-distributing the SOFTWARE.
%
% 2) The AUTHOR and CREWES must be acknowledged in any resulting publications or
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%compute radial distance
[nz,nx]=size(shot);
x=x(:)';
z=z(:);
xx=ones(nz,1)*x;
zz=z*ones(1,nx);
r=sqrt((xx-xshot).^2+(zz-zshot).^2);

shotg=shot.*r;